Occupant protection device for vehicle

ABSTRACT

An occupant protection device includes: a controller; first and second bus lines; a first collision sensor arranged on a side of the vehicle, and transmitting a first signal to the controller via the first bus line; a second collision sensor arranged on a center of the vehicle, and transmitting a second signal to the controller via the second bus line; and a third collision sensor arranged on a front side from the first collision sensor, and transmitting a third signal to the controller via the second bus line. The controller determines the collision on the side of the vehicle based on the first and second signals. The controller determines the collision on a part of the vehicle based on the third signal, the part disposed on the front side from the first collision sensor. The controller activates an occupant protection element.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2008-42966filed on Feb. 25, 2008, the disclosure of which is incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to an occupant protection device havingmultiple sensors for detecting collision of a vehicle. A signal of thecollision is transmitted from the sensors through a bus line.

BACKGROUND OF THE INVENTION

An occupant protection device for a vehicle includes multiple sensorsfor detecting collision of the vehicle and a bus line for transmitting asignal of the collision therethrough. JP-A-2007-215102 corresponding toUS Patent Application Publication No. 2007/0233919 teaches an air bagdevice as the occupant protection device. The air bag device includesmultiple slave sensors, an air bag ECU, a driver side air bag, apassenger side air bag, a side air bag, a curtain air bag and the like.

The slave sensors are arranged on a right front side, a left front side,a right side near a B pillar, the right side near a C pillar, a leftside near the B pillar and the left side near the C pillar in thevehicle. The slave sensors on the right and left front sides detectacceleration in a front-rear direction of the vehicle, and transmitsignals via a communication bus line. The slave sensor on the rightfront side is connected to an air bag ECU via a communication bus line,which is different from a bus line for the slave sensor on the leftfront side. The slave sensor on the left front side is connected to theair bag ECU via another communication bus line. The slave sensors on theright side near the B pillar and the right side near the C pillar detectacceleration in a right-left direction of the vehicle, and transmitsignals via a communication bus line, which is different from a bus linefor the slave sensors on the left side near the B pillar and the leftside near the C pillar. The slave sensors on the right side near the Bpillar and the right side near the C pillar are connected to the air bagECU via a communication bus line, and the slave sensors on the left sidenear the B pillar and the left side near the C pillar are connected tothe air bag ECU via another communication bus line.

The air bag ECU includes an internal acceleration sensor in the ECU. TheECU determines based on detection results of the slave sensors and theinternal acceleration sensor whether the collision occurs. The ECUcontrols inflation of the driver side air bag, the passenger side airbag, the side air bag and the curtain air bag. Specifically, based onthe detection results of the slave sensors on the right and left frontsides of the vehicle and the internal acceleration sensor, the ECUcontrols the inflation of the driver side air bag and the passenger sideair bag. Based on the detection results of the slave sensors on theright and left sides near the B pillar and the internal accelerationsensor, the ECU controls the inflation of the side air bag. Based on thedetection results of the slave sensors on the right and left sides nearthe C pillar and the internal acceleration sensor, the ECU controls theinflation of the curtain air bag.

In the air bag device, the air bag ECU is arranged at a position on afront side from a center of the vehicle. Therefore, even when the sideof the vehicle near the C pillar collides with an object, the ECU is farapart from the collision portion of the vehicle. Thus, the internalacceleration sensor in the ECU cannot accurately detect the accelerationgenerated by the collision.

In view of the above difficulty, as shown in FIG. 7, a slave sensor 10is arranged at a center in the right-left direction of the vehicle nearthe C pillar. The sensor 10 detects the acceleration in the right-leftdirection of the vehicle, and the sensor transmits a signal to the airbag ECU 11 via a communication bus line. The ECU 11 controls theinflation of the curtain air bag based on the detection results of theslave sensors 12, 13 near the C pillar and the slave sensor 10 at thecenter of the vehicle. The sensors 12, 13 on the side of the vehiclenear the C pillar function as a main sensor, and the sensor 10 at thecenter of the vehicle near the C pillar functions as a safing sensor. Ifthe slave sensors 12, 13 and the slave sensor 10 are connected to theECU 11 via the same communication bus line, the main sensor and thesafing sensor are connected to the ECU via the same line. Therefore,when the line is down, the ECU 11 may mistake to detect the collision.Accordingly, as shown in FIG. 7, the sensors 12, 13 near the C pillarare respectively connected to the ECU 11 via the line B1, B2, which isdifferent from the line B3 for the sensor 10 at the center of thevehicle. Thus, the number of the bus lines increases.

SUMMARY OF THE INVENTION

In view of the above-described problem, it is an object of the presentdisclosure to provide an occupant protection device having multipledetection elements for detecting collision of a vehicle.

According to a first aspect of the present disclosure, an occupantprotection device for a vehicle includes: a controller; first and secondbus lines; a first collision detection element arranged on a side of thevehicle, detecting a collision in a right-left direction of the vehicle,and transmitting a first detection signal to the controller via thefirst bus line; a second collision detection element arranged on acenter of the vehicle in the right-left direction of the vehicle,detecting the collision in the right-left direction of the vehicle, andtransmitting a second detection signal to the controller via the secondbus line; and a third collision detection element arranged on a frontside from the first collision detection element, detecting thecollision, and transmitting a third detection signal to the controllervia the second bus line. The controller determines the collision on theside of the vehicle based on the first and second detection signals fromthe first and second collision detection elements. The controllerdetermines the collision on a part of the vehicle based on the thirddetection signal from the third collision detection element. The part ofthe vehicle is disposed on the front side from the first collisiondetection element. The controller controls to activate an occupantprotection element corresponding to the collision. The first bus line isdifferent from the second bus line.

In the above device, the first collision detection element is connectedto the controller via the first bus line, which is different from thesecond bus line for connecting the second collision detection element tothe controller without increasing the number of bus lines.

According to a second aspect of the present disclosure, an occupantprotection device for a vehicle includes: a controller; first to fourthbus lines; a second row right side collision sensor arranged on a rightside of the vehicle near a second row of seats, detecting anacceleration in a right-left direction of the vehicle, and transmittinga signal to the controller via the first bus line; a second row leftside collision sensor arranged on a left side of the vehicle near thesecond row of seats, detecting an acceleration in the right-leftdirection of the vehicle, and transmitting a signal to the controllervia the first bus line; a first row right side collision sensor arrangedon the right side of the vehicle near a first row of seats, detecting anacceleration in the right-left direction of the vehicle, andtransmitting a signal to the controller via the second bus line; a firstrow left side collision sensor arranged on the left side of the vehiclenear the first row of seats, detecting an acceleration in the right-leftdirection of the vehicle, and transmitting a signal to the controllervia the second bus line; a center collision sensor arranged on a centerof the vehicle in the right-left direction, detecting an acceleration inthe right-left direction of the vehicle, and transmitting a signal tothe controller via the second bus line; a right front side collisionsensor arranged on a right front side of the vehicle, detecting anacceleration in a front-rear direction of the vehicle, and transmittinga signal to the controller via the third bus line; and a left front sidecollision sensor arranged on a left front side of the vehicle, detectingan acceleration in the front-rear direction of the vehicle, andtransmitting a signal to the controller via the fourth bus line. Thefirst to fourth bus lines are different from each other.

In the above device, the second row and left right side collisionsensors are connected to the controller via the first bus line, which isdifferent from the second bus line for connecting the center collisionsensor to the controller without increasing the number of bus lines.

According to a third aspect of the present disclosure, an occupantprotection device for a vehicle includes: a controller; first right andleft side bus lines and second right and left side bus lines; a firstrow right side collision sensor arranged on a right side of the vehiclenear a first row of seats, detecting an acceleration in a right-leftdirection of the vehicle, and transmitting a signal to the controllervia the first right side bus line; a second row right side collisionsensor arranged on the right side of the vehicle near a second row ofseats, detecting an acceleration in the right-left direction of thevehicle, and transmitting a signal to the controller via the first rightside bus line; a first row left side collision sensor arranged on a leftside of the vehicle near the first row of seats, detecting anacceleration in the right-left direction of the vehicle, andtransmitting a signal to the controller via the first left side busline; a second row left side collision sensor arranged on the left sideof the vehicle near the second row of seats, detecting an accelerationin the right-left direction of the vehicle, and transmitting a signal tothe controller via the first left side bus line; a center collisionsensor arranged on a center of the vehicle in the right-left direction,detecting an acceleration in the right-left direction of the vehicle,and transmitting a signal to the controller via the second left side busline; a left front side collision sensor arranged on a left front sideof the vehicle, detecting an acceleration in a front-rear direction ofthe vehicle, and transmitting a signal to the controller via the secondleft side bus line; and a right front side collision sensor arranged ona right front side of the vehicle, detecting an acceleration in afront-rear direction of the vehicle, and transmitting a signal to thecontroller via the second right side bus line. The first right and leftside bus lines and the second right and left side bus lines aredifferent from each other.

In the above device, the first and second row right side collisionsensors are connected to the controller via the first right side busline, which is different from the second left side bus line forconnecting the center collision sensor to the controller withoutincreasing the number of bus lines. Further, the first and second rowleft side collision sensors are connected to the controller via thefirst left side bus line, which is different from the second left sidebus line for connecting the center collision sensor to the controllerwithout increasing the number of bus lines.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a diagram showing an occupant protection device according to afirst embodiment;

FIG. 2 is a block diagram showing a controller in FIG. 1;

FIG. 3 is a diagram showing an occupant protection device according to amodification of the first embodiment;

FIG. 4 is a block diagram showing a controller in FIG. 3;

FIG. 5 is a diagram showing an occupant protection device according to asecond embodiment;

FIG. 6 is a block diagram showing a controller in FIG. 5; and

FIG. 7 is a diagram showing an air bag device according to a prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present inventor has studied about an occupant protection device fora vehicle having first and second collision detection elements, whichare independently connected to a controller via bus lines withoutincreasing the number of bus lines. In the device, the first collisiondetection element is connected to the controller via the first bus line,and the second collision detection element is connected to thecontroller via the second bus line. The third collision detectionelement is connected to the controller via the same second bus line, sothat the number of bus lines does not increase.

First Embodiment

An occupant protection device 1 for a vehicle according to a firstembodiment is shown in FIG. 1. The vehicle includes two rear seats sothat the vehicle includes the first to third rows of seats in thefront-rear direction of the vehicle. RIGHT and LEFT in FIG. 1 representa right-left direction of the vehicle, and FRONT and REAR in FIG. 1represent a front-rear direction of the vehicle.

The device 1 provides to protect an occupant in the vehicle when thedevice 1 detects collision of a front and/or a side of the vehicle. Thedevice 1 includes a right front sensor 100, a left front sensor 101, afirst row right side sensor 102, a second row right side sensor 103, athird row right side sensor 104, a first row left side sensor 105, asecond row left side sensor 106, a third row left side sensor 107, acenter acceleration sensor 108 and a controller 109. The first row rightand left side sensors 102, 105 provide a third collision detectionelements, the second and third row right and left side sensors 103, 104,106, 107 provide a first collision detection element, and the centeracceleration sensor 108 provides a second collision detection element.The right and left front sensors 100, 101 detect longitudinalacceleration along with the front rear direction of the vehicle. Othersensors 102-108 detect lateral acceleration along with the right leftdirection of the vehicle.

The right front sensor 100 is arranged on a right front side of thevehicle, and detects the collision along with the front rear directionof the vehicle. The sensor 100 detects the acceleration and transmits asignal via a bus line. The left front sensor 101 is arranged on a leftfront side of the vehicle, and detects the collision along with thefront rear direction of the vehicle. The sensor 101 detects theacceleration and transmits a signal via the bus line. The right and leftfront sensors 100, 101 are mounted in a front bumper, for example.

The first right side sensor 102 is arranged on a right side of the firstrow of the seats, which is disposed on a front side from a center of thevehicle. The sensor 102 detects the collision along with the right leftdirection of the vehicle, detects the acceleration, and transmits asignal via the bus line. The second and third right side sensors 103,104 are arranged on the right side of the vehicle of the second andthird rows of the seats, which are on a rear side from the first rightside sensor 102. The sensors 103, 104 detect the acceleration in theright and left direction of the vehicle, and transmit signals via thebus line. The first left side sensor 105 is arranged on a left side ofthe first row of the seats, which is disposed on the front side from thecenter of the vehicle. The sensor 105 detects the collision along withthe right left direction of the vehicle, detects the acceleration, andtransmits a signal via the bus line. The second and third left sidesensors 106, 107 are arranged on the left side of the vehicle of thesecond and third rows of the seats, which are on a rear side from thefirst left side sensor 105. The sensors 106, 107 detect the accelerationin the right and left direction of the vehicle, and transmit signals viathe bus line. The right and left side sensors 102, 105 are mounted in adoor, for example.

The center acceleration sensor 108 is arranged at a center in the rightleft direction of the vehicle, which is disposed on a rear side from theside sensors 102, 105. The sensor 108 detects the collision in the rightleft direction of the vehicle. Specifically, the sensor 108 detects theacceleration, and transmits a signal via the bus line.

The controller 109 determines the collision based on the detectionresults of the sensors 100-108 and an internal sensor in the controller109, and controls inflation of an air bag as an occupant protectionelement and function of a pre-tensioner as another occupant protectionelement.

The right front sensor 100 is connected to the controller 109 via a busline B10, and the left front sensor 101 is connected to the controller109 via a bus line B11. The first right side sensor 102, the first leftside sensor 105 and the center acceleration sensor 108 are connected tothe controller 109 via a bus line B12 as a first bus line. The secondand third right side sensors 103, 104 and the second and third left sidesensors 106, 107 are connected to the controller 109 via a bus line B13as a second bus line. Thus, the second and third right side sensors 103,104 and the second and third left side sensors 106, 107 are connected tothe controller 109 via the second bus line B13, which is different fromthe first bus line B12 for connecting the center acceleration sensor 108to the controller 109.

The controller 109 will be explained with reference to FIG. 2. In FIG.2, I/F represents a bus interface, and PC represents a micro computer.

The controller 109 includes a longitudinal acceleration sensor 109 a, alatitudinal accelerations sensor 109 b, first to fourth bus interfacecircuits 109 c-109 f, an ignition circuit 109 g and a micro computer 109h.

The longitudinal acceleration sensor 109 a is disposed in the controller109, and detects the collision along with the front rear direction ofthe vehicle. The sensor 109 a detects the acceleration in the front reardirection of the vehicle. The latitudinal acceleration sensor 109 b isdisposed in the controller 109, and detects the collision along with theright left direction of the vehicle. The sensor 109 b detects theacceleration in the right left direction of the vehicle.

The first to fourth bus interface circuits 109 c-109 f convert thedetection results transmitted from the sensors 100-108 via the bus linesB10-B13 to a predetermined format, and input the results having thepredetermined format into the micro computer 109 h. The first to fourthbus interface circuits 109 c-109 f are integrated into one body as a businterface IC. The first bus interface circuit 109 c is connected to theright front sensor 100 via the bus line B10. The second bus interfacecircuit 109 d is connected to the left front sensor 101 via the bus lineB11. The third bus interface circuit 109 e is connected to the firstright side sensor 102, the first left side sensor 105 and the centeracceleration sensor 108 via the bus line B12. The fourth bus interfacecircuit 109 f is connected to the second and third right side sensors103, 104 and the second and third left side sensors 106, 107 via the busline B13. Further, the first to fourth bus interface circuits 109 c-109f are connected to the micro computer 109 h.

The ignition circuit 109 g activates the air bag and the pretensionerbased on an ignition signal or an activation signal from the microcomputer 109 h.

The micro computer 109 h determines the collision of the vehicle basedon the detection results inputted from the sensors 100-108 via the firstto fourth bus interface circuits 109 c-109 f and the detection resultsfrom the sensors 109 a-109 b. The micro computer 109 h outputs theignition signal for activating the air bag and the pretensioner to theignition circuit 109 g. Here, the air bag and the pretensionercorrespond to the collision of the vehicle. Specifically, the microcomputer 109 h detects the collision on the front side of the vehiclebased on the detection results of the longitudinal acceleration sensor109 a, the right front sensor 100 and the left front sensor 101, and themicro computer 109 h outputs the ignition signal for activating the airbag and the pretensioner corresponding to the collision on the frontside of the vehicle. The micro computer 109 h detects the collision onthe side of the vehicle near the first row of the seats based on thedetection results of the latitudinal acceleration sensor 109 b, thefirst right side sensor 102, and the first left side sensor 105, and themicro computer 109 h outputs the ignition signal for activating the airbag and the pretensioner corresponding to the collision on the side ofthe vehicle near the first row of the seats. The micro computer 109 hdetects the collision on the side of the vehicle near the second row ofthe seats based on the detection results of the second right side sensor103, the second left side sensor 106 and the center acceleration sensor108, and the micro computer 109 h outputs the ignition signal foractivating the air bag and the pretensioner corresponding to thecollision on the side of the vehicle near the second row of the seats.The micro computer 109 h detects the collision on the side of thevehicle near the third row of the seats based on the detection resultsof the third right side sensor 104, the third left side sensor 107 andthe center acceleration sensor 108, and the micro computer 109 h outputsthe ignition signal for activating the air bag and the pretensionercorresponding to the collision on the side of the vehicle near the thirdrow of the seats.

The micro computer 109 h is connected to both of the longitudinalacceleration sensor 109 a and the latitudinal acceleration sensor 109 b.Further, the micro computer 109 h is connected to the first to fourthbus interface circuits 109 c-109 f and the ignition circuit 109 g.

The functions of the occupant protection device will be explained withreference to FIGS. 1 and 2.

When the collision on the right side of the vehicle near the first rowof the seats occurs, the acceleration, i.e., the impact corresponding tothe collision is generated. The acceleration is remarkably detected bythe first right side sensor 102. Further, the collision is also detectedby the latitudinal acceleration sensor 109 b in the controller 109. Thedetection result of the first right side sensor 102 is transmitted tothe controller 109 via the bus line B12. The transmitted result isconverted by the third bus interface circuit 109 e to have apredetermined format. Then, the converted result is input in the microcomputer 109 h. Further, the detection result of the latitudinalacceleration sensor 109 b is also input in the micro computer 109 h.

The micro computer 109 h determines the collision on the side of thevehicle near the first row of seats on the basis of the detectionresults of the first right side sensor 102 and the latitudinalacceleration sensor 109 b. Specifically, when an integration value ofthe acceleration per a predetermined interval that is detected by thefirst right side sensor 102 exceeds a predetermined threshold, and whenan integration value of the acceleration per a predetermined intervalthat is detected by the latitudinal acceleration sensor 109 b exceeds apredetermined threshold, the micro computer 109 h determines that thecollision on the right side of the vehicle near the first row of seatsoccurs. Then, the micro computer outputs the ignition signal foractivating the air bag and the pretensioner corresponding to thecollision on the right side of the vehicle near the first row of seats.When the ignition signal is input in the ignition circuit 109 g, theignition circuit 109 g activates the air bag and the pretensioner basedon the ignition signal. Thus, the air bag and the pretensioner protectthe occupant.

When the collision on the right side of the vehicle near the second rowof seats occurs, the acceleration in the right left direction isgenerated. The acceleration is remarkably detected by the second rightside sensor 103. Further, the acceleration is also detected by thecenter acceleration sensor 108. The detection result of the second rightside sensor 103 is transmitted to the controller 109 via the bus lineB13. The transmitted result is converted to have a predetermined formatby the fourth bus interface circuit 109 f. Then, the converted result isinput in the micro computer 109 h. The detection result of the centeracceleration sensor 108 is input in the controller 109 via the bus lineB12. The transmitted result is converted to have a predetermined formatby the third bus interface circuit 109 e. Then, the converted result isinput in the micro computer 109 h.

The micro computer 109 h determines the collision on the right side ofthe vehicle near the second row of seats on the basis of the detectionresults of the second right side sensor 103 and the center accelerationsensor 108. Specifically, when an integration value of the accelerationper a predetermined interval that is detected by the second right sidesensor 103 exceeds a predetermined threshold, and when an integrationvalue of the acceleration per a predetermined interval that is detectedby the center acceleration sensor 108 exceeds a predetermined threshold,the micro computer 109 h determines that the collision on the right sideof the vehicle near the second row of seats occurs. Then, the microcomputer 109 h outputs the ignition signal for activating the air bagand the pretensioner corresponding to the collision on the right side ofthe vehicle near the second row of seats. When the ignition signal isinput in the ignition circuit 109 g, the ignition circuit 109 gactivates the air bag and the pretensioner based on the ignition signal.Thus, the air bag and the pretensioner protect the occupant.

When the collision on the right side of the vehicle near the third rowof seats occurs, the acceleration in the right left direction isgenerated. The acceleration is remarkably detected by the third rightside sensor 104. Further, the acceleration is also detected by thecenter acceleration sensor 108. Similar to a case where the collision onthe right side of the vehicle near the second row of seats occurs, basedon the detection results of the third right side sensor 104 and thecenter acceleration sensor 108, the air bag and the pretensionercorresponding to the collision on the right side of the vehicle near thethird row of seats are activated so that the air bag and thepretensioner protect the occupant.

Similar to cases where the collisions on the right side of the vehiclenear the first to third rows of seats, when the collision on the leftside of the vehicle near the first, second or third row of seats occurs,the collision is detected by using the first to third left side sensors105-107, the center acceleration sensor 108, and the latitudinalacceleration sensor 109 b in the controller 109.

When the collision on the right front side of the vehicle occurs, theacceleration in the right left direction is generated. The accelerationis remarkably detected by the right front sensor 100. Further, theacceleration is also detected by the longitudinal acceleration sensor109 a in the controller 109. The detection result of the right frontsensor 100 is transmitted to the controller 109 via the bus line B10.The transmitted result is converted to have a predetermined format bythe first bus interface circuit 109 c. Then, the converted result isinput in the micro computer 109 h. The detection result of thelongitudinal acceleration sensor 109 a is input in the controller 109.

The micro computer 109 h determines the collision on the right frontside of the vehicle on the basis of the detection results of the rightfront sensor 100 and the longitudinal acceleration sensor 109 a.Specifically, when an integration value of the acceleration per apredetermined interval that is detected by the right front sensor 100exceeds a predetermined threshold, and when an integration value of theacceleration per a predetermined interval that is detected by thelongitudinal acceleration sensor 109 a exceeds a predeterminedthreshold, the micro computer 109 h determines that the collision on theright front side of the vehicle occurs. Then, the micro computer 109 houtputs the ignition signal for activating the air bag and thepretensioner corresponding to the collision on the right front side ofthe vehicle. When the ignition signal is input in the ignition circuit109 g, the ignition circuit 109 g activates the air bag and thepretensioner based on the ignition signal. Thus, the air bag and thepretensioner protect the occupant.

In this embodiment, the controller 109 determines the collision on theside of the vehicle near the second and third rows of seats based on thedetection results of the sensors 103-104, 106-108. The sensors 103-104,106-107 are connected to the controller 109 via the bus line B13, whichis different from the bus line B12 for connecting the sensors 102, 105to the controller 109. The center acceleration sensor 108 is connectedto the controller 109 via the bus line B12 for connecting the sensors102, 105 to the controller 109. Accordingly, the sensors 103-104,106-107 for detecting the collision on the side of the vehicle near thesecond and third rows of seats are connected to the controller 109 viathe bus line B13, which is different from the bus line B12 forconnecting the sensor 108 to the controller 109. Further, it is notnecessary to add a new independent bus line for connecting the sensor108 to the controller 109. Accordingly, without increasing the number ofbus lines, the sensors 103, 104, 106-107 for detecting the collision onthe side of the vehicle near the second and third rows of seats isconnected to the controller 109 via the bus line B13, which is differentfrom the bus line B12 for connecting the center acceleration sensor 108to the controller 109.

The vehicle has three rows of seats in the front rear direction of thevehicle. Alternatively, the vehicle may have one, two or more than threerows of seats. FIG. 3 shows the vehicle having two rows of seats. Inthis case, the third right side sensor 104 and the third left sidesensor 107 are removed from the device in FIG. 1. FIG. 4 shows anoccupant protection device 2 with bus lines B10-B13 and the sensors100-103, 105-106, 108.

Second Embodiment

An occupant protection device 3 for a vehicle according to a secondembodiment will be explained. In the device, a bus line B21 forconnecting to the center acceleration sensor 208 is arranged differentlyfrom the bus line B11 in FIG. 1. Specifically, the bus line B21 forconnecting to the center acceleration sensor 208 is also connected tothe left front sensor 201.

FIG. 5 shows an occupant protection device 3 according to a secondembodiment. FIG. 6 shows a block diagram of a controller 209.

The device 3 includes a right front sensor 200, a left front sensor 201as a third collision detection element, a first right side sensor 202, asecond right side sensor 203, a third right side senor 204, a first leftside sensor 205, a second left side sensor 206, a third left side sensor207, a center acceleration sensor 208 as a second collision detectionelement and a controller 209. The second and third right side sensors203, 204 and the second and third left side sensors 206, 207 provide afirst collision detection element.

The right front sensor 200 is connected to the controller 209 via thebus line B20. The left front sensor 201 and the center accelerationsensor 208 are connected to the controller 209 via the bus line B21 as asecond bus line. Specifically, the center acceleration sensor 208 isarranged on a controller side from the left front sensor 201. Thus, thecenter acceleration sensor 208 is disposed on the nearest side of thecontroller 209 in the bus line B21. The first to third right sidesensors 202-204 are connected to the controller 209 via the bus line B23as a first bus line. Further, the first to third left side sensors205-207 are connected to the controller 209 via the bus line B22 as thefirst bus line. Thus, the bus line B23 for the side sensors 203, 204,the bus line B22 for the side sensors 206, 207 and the bus line B21 forthe center acceleration sensor 208 are different from each other.

As shown in FIG. 6, the controller 209 includes a longitudinalacceleration sensor 209 a, a latitudinal accelerations sensor 209 b,first to fourth bus interface circuits 209 c-209 f, an ignition circuit209 g and a micro computer 209 h.

The first bus interface circuit 209 c is connected to the right frontsensor 200 via the bus line B20. The second bus interface circuit 209 dis connected to the left front sensor 201 and the center accelerationsensor 208 via the bus line B21. The third bus interface circuit 209 eis connected to the first to third right side sensors 202-204 via thebus line B23. The fourth bus interface circuit 209 f is connected to thefirst to third left side sensors 205-207 via the bus line B22.

The functions of the device 3 in FIG. 6 are similar to that of thedevice 1 in FIG. 2.

The controller 209 determines the collision on the side of the vehiclenear the second and third rows of seats based on the detection resultsof the second and third right side sensors 203, 204, the second andthird left side sensors 206, 207 and the center acceleration sensor 208.The second and third right side sensors 203, 204 are connected to thecontroller 209 via the bus line B22, which is different from the busline B21 for connecting to the left front sensor 201. The second andthird left side sensors 206, 207 are connected to the controller 209 viathe bus line B23, which is different from the bus line B21 forconnecting to the left front sensor 201. The center acceleration sensor208 is connected to the controller 209 via the bus line B21, which isthe same bus line B21 for connecting to the left front sensor 201. Thus,the second and third right side sensors 203, 204 for detecting thecollision on the right side of the vehicle near the second and thirdrows of seats are connected to the controller 209 via the bus line B23,which is different from the bus line B21 for connecting to the centeracceleration sensor 208. The second and third left side sensors 206, 207for detecting the collision on the left side of the vehicle near thesecond and third rows of seats are connected to the controller 209 viathe bus line B22, which is different from the bus line B21 forconnecting to the center acceleration sensor 208. Further, it is notnecessary to add a new independent bus line for connecting the centeracceleration sensor 208 and the controller 209. Thus, without increasingthe number of bus lines, the bus line B21 for connecting to the centeracceleration sensor 208, the bus line B23 for connecting to the secondand third right side sensors 203, 204, and the bus line B22 forconnecting to the second and third left side sensors 206, 207 aredifferent from each other.

The center acceleration sensor 208 is connected to the controller 209via the bus line B21, which connects to the left front sensor 201.Further, the center acceleration sensor 208 is arranged on a controllerside from the left front sensor 201. Thus, the center acceleration senor208 is disposed on the nearest side of the controller 209 in the busline B21. Accordingly, transmission failure of the detection resultsfrom the center acceleration sensor 208 to the controller 209 islimited. The transmission failure is occurred by disconnection of buslines caused by the collision. Thus, even when a secondary collision tothe side of the vehicle occurs, the device 3 protects the occupant basedon the detection result of the center acceleration sensor 208.

While the invention has been described with reference to preferredembodiments thereof, it is to be understood that the invention is notlimited to the preferred embodiments and constructions. The invention isintended to cover various modification and equivalent arrangements. Inaddition, while the various combinations and configurations, which arepreferred, other combinations and configurations, including more, lessor only a single element, are also within the spirit and scope of theinvention.

What is claimed is:
 1. An occupant protection device for a vehiclecomprising: a controller; first to fourth bus lines; a second row rightside collision sensor arranged on a right side of the vehicle near asecond row of seats, detecting an acceleration in a right-left directionof the vehicle, and transmitting a signal to the controller via thefirst bus line; a second row left side collision sensor arranged on aleft side of the vehicle near the second row of seats, detecting anacceleration in the right-left direction of the vehicle, andtransmitting a signal to the controller via the first bus line; a firstrow right side collision sensor arranged on the right side of thevehicle near a first row of seats, detecting an acceleration in theright-left direction of the vehicle, and transmitting a signal to thecontroller via the second bus line; a first row left side collisionsensor arranged on the left side of the vehicle near the first row ofseats, detecting an acceleration in the right-left direction of thevehicle, and transmitting a signal to the controller via the second busline; a center collision sensor arranged on a center of the vehicle inthe right-left direction, detecting an acceleration in the right-leftdirection of the vehicle, and transmitting a signal to the controllervia the second bus line; a right front side collision sensor arranged ona right front side of the vehicle, detecting an acceleration in afront-rear direction of the vehicle, and transmitting a signal to thecontroller via the third bus line; and a left front side collisionsensor arranged on a left front side of the vehicle, detecting anacceleration in the front-rear direction of the vehicle, andtransmitting a signal to the controller via the fourth bus line, whereinthe first to fourth bus lines are different from each other, wherein thecontroller determines a collision on at least one side of the vehiclebased on the signals from the first and second row right side collisionsensors, the first and second row left side collision sensors and thecenter collision sensor, wherein the controller, the first row left sidecollision sensor, the center collision sensor and the first row rightside collision sensor are coupled in this order, and wherein thecontroller, the second row right side collision sensor and the secondrow left side collision sensor are coupled in this order.
 2. An occupantprotection device for a vehicle comprising: a controller; first tofourth bus lines; a second row right side collision sensor arranged on aright side of the vehicle near a second row of seats, detecting anacceleration in a right-left direction of the vehicle, and transmittinga signal to the controller via the first bus line; a second row leftside collision sensor arranged on a left side of the vehicle near thesecond row of seats, detecting an acceleration in the right-leftdirection of the vehicle, and transmitting a signal to the controllervia the first bus line; a first row right side collision sensor arrangedon the right side of the vehicle near a first row of seats, detecting anacceleration in the right-left direction of the vehicle, andtransmitting a signal to the controller via the second bus line; a firstrow left side collision sensor arranged on the left side of the vehiclenear the first row of seats, detecting an acceleration in the right-leftdirection of the vehicle, and transmitting a signal to the controllervia the second bus line; a center collision sensor arranged on a centerof the vehicle in the right-left direction, detecting an acceleration inthe right-left direction of the vehicle, and transmitting a signal tothe controller via the second bus line; a right front side collisionsensor arranged on a right front side of the vehicle, detecting anacceleration in a front-rear direction of the vehicle, and transmittinga signal to the controller via the third bus line; a left front sidecollision sensor arranged on a left front side of the vehicle, detectingan acceleration in the front-rear direction of the vehicle, andtransmitting a signal to the controller via the fourth bus line, a thirdrow right side collision sensor arranged on the right side of thevehicle near a third row of seats, detecting an acceleration in theright-left direction of the vehicle, and transmitting a signal to thecontroller via the first bus line; and a third row left side collisionsensor arranged on the left side of the vehicle near the third row ofseats, detecting an acceleration in the right-left direction of thevehicle, and transmitting a signal to the controller via the first busline, wherein the first to fourth bus lines are different from eachother, and wherein the controller determines a collision on at least oneside of the vehicle based on the signals from the first and second rowright side collision sensors, the first and second row left sidecollision sensors and the center collision sensor.